Structure And Properties Of The Ag Surface Modified TiNi Alloys

In the biomedical field,TiNi alloy has a wide range of applicationsdue to theunique shape memory effect and superelasticity, good mechanical properties andbiocompatibility. To broaden the TiNi alloy applications in the medical field, thereare two ways to give antibacterial properties of TiNi alloy, first, prepared TiNiAgalloy by arc melting, then modified its surface by laser remelting; second, preparedTiNiAg alloy by Ag ion-implanted TiNi. The structure and properties of TiNiAgwere studied by used SEM, DSC, XRD, TEM, EDS, AFM, hardness tester,electrochemical workstation and antibacterial test.The result showed that the Ag in the TiNi matrix solubility was improved by laserremelting.The Ms of the TiNiAg alloy decreased with increased of the Ag. The mainlyphase of TiNiAg cast alloy was B19(martensite). The mainly phase of TiNiAgalloy by laser remelting was B2(parent phase).The surface of the TiNi alloy is mainly consist of O, Ti and Ag after Ag ionimplantation, and Ag mainly exists in the form of simple substance. With theincreasing of the implantation dose on the surface of alloy, the surface roughnessdecreases at first and then increases. The alloy surface has lowest roughness whenthe implantation dose is4×1017ions/cm2.With the introduction of Ag element, the hardness of TiNi alloy decreases;Laser remelting can enhance the hardness, this is due to laser remelting can refinethe crystalline grain and the formation of austenite.The introduction of Ag in alloy can improve the corrosion resistance of alloy,this is due to Ag itself has good corrosion resistance, and the introduction of Agcan make Ti is more likely to oxidate and generate thicker oxide film, so as toimprove the corrosion resistance of the alloyThe introduction of Ag brings the antibacterial property in the TiNi alloys.And with the increasing of Ag content, the performance improves. This is due toAg reacts with body fluids and enter fluids in the form of Ag ions. Ag ions canpierce through the cell membranes and kill the bacterium. In this way, antibacterialeffect achieves.